Don't use var - use the actual variable type. It's not what's causing the problem in this case, it's that your caps KEY IS STUCK DOWN and you have spurious semicolons!
Try this:
public static void Main(string[] args)
{
int chess = 8;
string dark = "x";
string light = "y";
for (var line1 = 0; line1 < chess; line1++)
{
for (var column2 = 0; column2 < chess; column2++)
{
string result;
if (line1 == 0)
{
...
}
}
}
}
Semicolon is a statement terminator in C#, so when you put one at the end of your for loops:
for (var line1 = 0; line1 < chess; line1++) ;
{
for (var coloumn2 = 0; coloumn2 < chess; coloumn2++) ;
It ends the scope of the variable you declare within it.